Leg length adjusting apparatus



Nov. 3, 1959 DERBY ET AL LEG LENGTH ADJUSTING APPARATUS 3 Sheets-Sheet 2 Filed Sept. 22, 1955 mgr WDR

I E El 5 w." W Mr R RAW Nov. 3, 1959 DERBY ETAL 2,911,134

LEG LENGTH ADJUSTING APPARATUS Filed Sept. 22, 1955 5 Sheets-Sheet 3 INVENTORS' RICHQRD F'- DERBY 2,911,134 LEG LENGTH ADJUSTING APPARATUS liichard F. Derby, West Concord, and Arthur Biery,

Pine Island, Minn.

Application September 22, 1955, SerialNoi 535,897

13 Claims. (Cl. 182-201) This invention relates to apparatus for supporting articles such as ladders and other articles having depend ing support legs, and more particularly to apparatus for adjusting the lengths of such support legs so that they may be placed upon a surface having substantially any slope or contour to maintain the article in a desired position such as upright or level.

Many types of articles are commonly used by placing them on an irregular or uneven surface such as the ground surface.

ing, prospecting or military fieldmaneuve'rs. Although in most cases the surface of the ground could'be leveled to permit use of a conventional type article having legs of fixed length, it is frequently desired that the article should only be quickly and temporarily placed in a certain position and then removed for use elsewhere. Such is obviously the case in ladders which are used for a wide variety of purposes and such is also the case with equipment such as military field radios.- In addition to the placing of articles such as ladders on the ground, it is frequently necessary to rest a ladder against an unevenly contoured wall or surface such as the curved wall of a silo or such as the branches of a tree. these cases it is desirable to maintain the supports of the ladder in predetermined positions, wherein one rail of the ladder will be positioned at a distance from the Specific examples of such articles are ladders, loading platforms or ramps, tables for field use in surveywall which is different from the distance between the wall and the other'rail. These mentioned devices and their corresponding uses in connection with uneven surfaces are merely meant to be exemplary of many types;

position on even a slope or irregularly contoured surface.

Still another object of our'invention is to provide an improved apparatus of extremely rugged'construction and positive operation for simultaneously and positively looking adjustable support members after the same have all engaged a surface for adapting such support members to support an article in adesired position by merely holding the article in the desired position and then-placing itupon such a surface.

A further object of our invention is the provision of new apparatus which may be included as original equipment in and which may be applied as an attachment to the support members of an article and making such support members adjustable and for adapting them to be simultaneously locked in a desired position so that the article may be placed on an uneven surface and for 2,911,134 Patented Nov. 3, 1959 2 further adapting such support members to be released when the article is removed from the surface.

A still further object of our invention is to provide novel apparatus for use with articles which require a multiplicity of supports, which apparatus is adapted to adjust the relative lengths of support members for such an article so that it may be placed in a desired position on an uneven surface.

These and other'objects and advantages of our invention will more fully appear from the following description I made in connection with the accompanying drawings wherein like reference characters refer to the same parts throughout the several views and in which:

Fig. 1 is a front elevation view of our invention applied as an attachment to a ladder;

Fig. 2 is a detail perspective view, partly broken away, of a portion of the apparatus shown in Fig. 1;

Fig. 3 is a sectional detail view taken on a vertical plane extending substantially centrally through the apparatus shown in Fig. 2;

Fig. 4 is asectional detail view taken on a substantially horizontal plane through the apparatus shown in i Fig. 5 is a detail perspective view, partly broken away,

of a modifiedjform ofthe invention;

Fig. 6 is a detail sectional view of a portion of the Fig. 7 is a detail sectional view taken on a substantially horizontal plane through a shown in'Fig. 5;

Fig. 8 is a perspective view ofanother modification of the invention and being viewed from below the article to which theinvention is'attached;

Fig. 9 is a detail perspective View, partially broken away, of a portion of the invention shown in Fig. 8 and being'viewed from a position below the article to which the invention is attached;

Fig. 10 is a detail perspective View similar to Fig. 9, of another portion of the form of the invention shown in Fig.- 8;

Fig; ll'is a detailsection view taken on a substantially vertical plane through a portion of the invention shown in Fig. 8; and

Fig. 12 is'a'de'tail' section view of the portion of the invention shown in Fig. 11 and being taken on a subportion of the invention stantially vertical plane at'1212 of Fig. 11.

One embodiment of'the present invention is shown in Figs. 1 to 4 as an attachment to an article, which in the present form, consists of a ladder. 'T he ladder has the conventional upright side rails or support legs 10 and 11 and the conventional steps or cross rungs 12 ex t'en'ding between the rails 10 and 11 and afix'ed thereto. The laddermay also be provided with tierods l3 dis posed belowthe rungs 12 and secured as by nuts to the side rails. 1

We provide a pair of upright and elongated extensions.

14 and-15 which are respectively positioned adjacent the upright supports 10 and 11 and are mounted for vertical sliding thereon. Guide means are provided on the supports 10 and 1 1 for mounting the extensions 14 and 15'and in the'form shown, such means comprise tubular housings l6 and 17 which have caps 18 and 19 afiixed thereto, and which are secured to the ladder rails by means of mounting plates 20 and 21 which, in the form shown, are affixed to caps 18 and 19. As best The tubular housings 16 and 17 are alfixed at their lower ends to enclosures 2-2 and 23 respectively and which are identical to each other and which are best shown in Figs. 2 and 3. The tubular housings may be crimped and welded to the enclosures 22 and 23. Enclosures 22 and 23 are both provided with mounting ears through which screws may be extended to be afilxed into the ladder rails. Such mounting ears may be best seen in Figs. 2 and 3 on enclosure 22 where they are indicated by numeral 22a.

The lower portions of the enclosures 22 and 23 may be provided with suitable bushings 22b and 23b which receive and permit free sliding of the respective extensions 14 and 15.

The enclosures 22 and 23 house locking mechanisms which are indicated in general by numerals 24 and 25 which are substantially identical and which are adapted to lock and release the respective extensions. Because the locking mechanisms are substantially identical only one, the mechanism indicated 24, has been shown in detail and the description of it will sufiice for the description of both locking mechanisms 24 and 25.

Locking mechanism 24 is provided with a friction locking element 26, which in the form shown comprises a ring encircling the extension 14. The locking element 26 is provided with a pair of opposed gripping portions 27 and 28 which are respectively disposed on opposite sides of extension 14- and in close proximity therewith to frictionally engage'and grip the extension when-lock ing element 26 is swung upwardly into locking position. Locking element 26 is provided with extensions or arms 29 and 30 which respectively extend in opposite directions from the opposed gripping portions 27 and 28.

Stop means are provided for limiting vertical movement of locking element 26 and to fulcrum the same for vertical swinging. In the form shown, such stop means comprise a stopmember or bracket 31 which is affixed as by screws to the ladder rail 10. The substantially U-shaped bracket 31 encloses the fulcmmed projection 30 of locking element 26 and the upper portion 31a of stop member 31 restricts upward movement of projection 30 and the lower portion 31b restricts downward movement of projection 30.- i

A resiliently yieldable element 32, constituting in the form shown an annular rubber disc or bumper, is mounted on the projection 30 of the'frictional locking element 26. The annular rubber disc 32 compresses when the locking element 26 is shifted upwardly toward the upper portion 31a of stop member 31.

A lever or swing arm 33 extends through an elongated opening 34 in the forward portion of the enclosure 22 and extends generally parallel to the frictional locking element 26 and transversely of the extension 14. The lever arm 33 is connected with the projection 29 for vertical swinging with the locking element 26 by means of a pair of fingers 35 and 36 which respectively extend above and below the projection 29 and transversely thereof. The fingers 35 and 36 are spaced to permit limited vertical swinging of the locking element with respect thereto and to permit the projection 29 to shift'in its longitudinal direction therebetween.

Means are provided for limiting the downward swinging movement of the frictional locking element'26, and in the form shown, an abutment or stop element 37 is aflixed as by a screw 38 to the ladder rail 10 and positioned below the finger 36 to support the same when in its downwardly shifted position. The abutment 37 thererestricts the downward swinging of locking element Means are also provided for swinging the locking element 2.6 upwardly into locking position in response to upward movement of the extension 14 relative to the ladder rail 10. In the form shown, such means include an actuating element 38 which is mounted on the locking element 26 to swing therewith. Actuating elementjfgtl is held on the projection 30 by the annular rubber disc 32, as is best shown in Fig. 4 and the actuating element 38 includes a friction shoe portion 39 which frictionally engages one side of the extension 14 and thereby connects the locking element 26 with extension 14. The resilient rubber disc 32 urges the friction shoe 39 into engagement with the extension 14 which tends to cause upward swinging of the locking element 26 as extension 14 rises and passes through the locking element 26.

It will be remembered that the locking mechanism 25 is substantially identical to the locking mechanism 24 and all the parts of locking mechanism 24 are present in the locking mechanism 25 and arranged in substantially the same manner.

An interconnection 40 is provided between the upright supports 10 and 11 and is mounted thereon for rotary oscillation and in the form shown, the interconnection 40 comprises a rod or shaft having a manually operable length adjusting device 41 connected in the central portion thereof, and being mounted in bearings 42 which are aflixed to the rails 10 and 11. The interconnection 40 is connected with the swing arms 33 of both locking mechanisms to rotate when the same are swung. The manually operated length adjuster al may comprise a sleeve keyed to the two separate portions of interconnection 40 to cause the same to rotate together but to permit the same to be shifted sli htly apart or together so as to adjust the length of the interconnection.

. Manual means are also provided for releasing the locking device 24 from its upwardly swung locked position, and in the form shown, such means comprise a finger ring 43 which may be manually gripped and which is attached to a rod 44 which extends through the bottom of enclosure 22 and is swingably connected with the swing arm 33.

Means are associated with each of the extensions 14 and 15 for limiting the movement thereof. The mechanism associated with each of the extensions is substantially identical and a description of one is sufiicient for an understanding of both. As best shown in Figs. 2 and 3 the extension 14 is provided with an elongated slot 45 therein having upper and lower abutment surfaces 450 and 45b respectively. A lug 46, which may comprise a screw is threadedly carried in the housing 16 and e1: tends into the slot 45 for engaging the upper and lower surfaces thereofand limiting movement of extension 14. Lug 46 may be shifted to the other threaded aperture 47 in housing 16 to change the limit s of movement of extension 14 and thereby causethe'same to operate between limits in'a higher position'in'housing 16. Means are also provided for continuously urging the extensions 14 and 15in a downward direction relative to supports 10 and 11. The mechanism for accomplishing such purposes is identical in connection with both of the extensions 14 and 15. As shown in Fig. 2, a resiliently yieldable compression spring 48 is mounted within the housing 16 and in engagement with the upper end of extension 14 and the cap 18 for continuously urging the extension 14 in a downward direction;

Means are also providedfor holding the locking element 26 in upwardly swung locking position so as to per-j mit the extensions 14 and 15 to be retracted as far; as possible and then locked in such a position for transporting the ladder. In the form shown, such meanscomprise a thumb screw'49 threadably mounted in the housing 22 adjacent the projection 29 and finger 36. As best seen in Fig. 3, the thumb screw 49 when turned inwardly will hold the finger 36 in its upwardly swung position and will thereby hold the locking element 36 in its upwardly swung locking position. When-the ladder has to be transported the extensions may be retracted and the thumb screw 49 may be projected inwardly to cause the extensions tohe locked. Withdrawal of the thumb screw will again release the extensions for normal operation.

Inoper-a tion, the ladder will be manually lifted to be placed in the desired upright position-adjacent a wallor surface against which it is to rest. If the ground below the ladder is uneven one of the extensions, such as extension 14 willengage the ground before the other extension 15. Whenextension 14 engages the ground, it begins to move upwardly with respect to the corresponding support or leg against the force exerted by coil spring 48. Friction shoe 39 bears against the extension 14 and the friction therebetween tends to cause friction shoe 39 and locking element' 26. to rise with extension 14. However, if'locking element 26 is to swing upwardly, several other portions also swing upwardly, including swing arm 33, and the locking element, swing arm, and friction shoe of the locking mechanism '25. The weights of these several parts plus the friction between the friction shoe of mechanism 25 and the extension all combine to resist the upward swinging of locking element 26. As a result,

the extension 14 will slide, upwardly through locking element 26 and locking element 26 will remain in its downwardly swung unlocked position. As the ladder rails 10 and 11 are moved downwardly to bring the extension 15 into engagement with the ground surface, the extension 14 will continue to effectively slide upwardly with respect to leg 10'. When extension 15 engages the ground surface, it also tends to slide upwardly throughits' corresponding locking element and by action of the-* friction shoe of mechanism 25, tends to swing the corresponding locking element upwardly. The combined friction of the two friction shoes bearing against their respective extensions is sufiicient to cause simultaneous upward swinging of the locking elements of mechanisms 24 and 25 into locking positions with respect to their corresponding extensions 14 and 15. The projection andrubber disc 32 of mechanism 24 shift slightly upwardly into engagement with the upper portion 31a of stop member 31 which thereafter restricts upward movement of the rubber disc 32, and the corresponding portions of mechanism 25 operate in a similar manner. The locking element 26 thereupon fulcru'rns about the upper portion 31a of stop member 31 and the opposed gripping portions 27 and 28 swing into locking relation on extension 14. The locking element of mechanism 25 operates similarly. The weighLof the ladder and of a person thereon is carried by the extensions 14- and 15 through the'locking rings, the stop members, to the rails 10 and 11. The resilient disc 32 will compress slightly under the weight of the ladder to compensate for any small difierences of the construction :and assembly of any individual parts of the respective mechanisms 24 and 25.

If, for any reason, after the ladder has been placed on the ground in the manner indicated, the ladder is tilted tov remove one of the extensions such as 14 fr'omthe ground, the corresponding resilient rubber disc 32 will urge the projection 30 downwardly to maintain the lock- If for any reason, it is desired to release the exterisions Hand 15 without lifting the ladder from the ground, the ring 43may be manually pulled downwardly to cause downward swinging of the swing arms and the locking elements connected with the two locking mechanisms 24 andv 25.

The form of the invention shown in Figs. 5-7 is similar to. that'sliown in Figs. l.-4 withthe exception that the invention is,.in this application, built into support legs such as the side rails of a metallic ladder. The upright side rails 50 and 51 are generally rectangular in cross section and hollow and have the ladder rungs 52 extending therebetween and afiixed. thereto. A hollow enclosure 53' is aflixed to the lower portion of the legs 50 and 51 for enclosing the locking mechanisms therein. Extensions 54 and 55 extend upwardly through the opposite ends of the enclosure 53 and into the hollow interior of the tubular ladder rails 50 and 51 and are guided therein for vertical sliding movement. Means are provided forlimit ing. the vertical sliding movement of the extensions 54 and 55, and, such means are similar to that shown in the form of the invention shown in Figs. 1 to 4. The construction'for limiting the movement of each leg is sub: stantially identical and a description of one mechanism will'suffice. An elongated slot 56 is provided in extension 55 to define upper and lower abutment surfaces 56a.

A threaded lug57 extends through the leg 51 and into. the

. extensions 54 and 55 respectively. These mechanisms are substantially identical andare indicated in general by ing element 36 in its swung and locked position. The

extension 14 will thereby remain in a stationary position even though it is removed from the ground and it may later be replaced on the ground to again support the ladder and will be maintained in its previously attained position relative to its support leg 10.

When the ladder is manually lifted oft the ground, the

upper abutment surface of the slot in the extension is engaged thereby. v

The locking element 26 will return to its downwardly swung position and will be held in unlocked position by the abutment 37 upon which finger 36 rests.

numerals .58 and 59. The locking mechanisms 58 and 59' are provided "with. frictional locking elements 60. and 61;

which surround the vertically slidable extensions 54 and 55. The locking elements 60 and 61 each have opposed gripping portions disposed on opposite sides of the extensions 54 and 55 and in the. present form these gripping portions engage the inner and outer enlarged and flat surfaces of the extensions. As will be best seen in Fig. 6, the locking element 61 is swingable to the dotted position B thereof into locking frictional engagement with the.

corresponding extension 51, whereupon the opposed gripping portionsare swung into locking frictional engagement with the extension 55. The bottom of the enclosure 53 provides means for limiting the downward shifting of the locking elements so as tomaintain them in released position when the extensions 54 and 55 are removed from the, ground.

The locking mechanism 58 which is similar to locking mechanism 59 is shown in detail in Figs. 6 and.7. The

locking element 61 isprovid'ed with an inwardly ex- I tending arm 62' which is connected by means of a tension.

spring 63 to the bottom of enclosure 53. The spring 63 tends to restrict upward movement of the outer portion of projection 62. A stop member 64 is afiixed to the upper portion of the enclosure 53 to restrict upward movement of the projection 62 when locking element 61 is swung upwardly; Another lug or projection 65' extendsoutwardly fr'ojnslocking element 61 and within the enclosure 53. a The similar lug 66 of mechanism 59 is shown in Fig. 5. A'rotary interconnection 67 extends between the legs 50 and 5 1 and is journaled in bearings provided as shown in stop members 64. The rotary interconnection 67 is connected to each of the outstanding lugs 65 and 66 of the corresponding locking elements 61 and 60 by swing arms 68 and 69 respectively which are doubled back upon themselves adjacent their outer end portion to receive the respective lugs therein.

- Means are also provided in this form of the invention for shifting the locking elements60 and 61 upwardly r into locking position when the extensions 54 and 55 move upwardly into the legs 50 and 51. In this form of the invention, such meansinclude mechanism on each of the extensions 54 and 55 which are substantially identical,

The mechanism on extension 55 is shown and includes an actuating element 70 which projects upwardly along the inner side of extension 55 for movement through an aperture 71 in the bottom of enclosure 53 into engagement with the frictional locking element 61 in spaced relation with the stop member 64. Actuating element 70 is mounted on the extension 55 for vertical adjustment by means of a strap 72 which is held on the extension 55 by means of a tightening bolt and nut 73. A similar actuating element is mounted in a similar manner on the extension 54 and is mounted thereon for vertical adjustment by means of strap 74.

The operation of this form of the invention is substantially identical to that shown in Figs. 1 to 4 with the exception that the locking elements 60 and 61 are swung in a slightly dilferent manner. The actuating element 70 is adjusted in its vertical position so that it will not engage the locking element 61 until after the other 7 extension 54 has engaged the ground. This adjustment is dependent upon the slope of the ground or other surface upon which the ladder is to be placed. The actuating element on extension 54 will be similarly adjusted so that the ladder need not be turned around in order to place the ladder on surfaces having various slopes. When the ladder is placed on the ground, and afterboth extensions 54 and 55 have engaged the ground surface, the actuating element 70 will be projected through the aperture 71 in enclosure 53 and into engagement with the locking element 61, locking element 61 will thereupon be swung upwardly and into frictional locking relation on the extension 55. Upward swinging of locking element 61 causes upward swinging of the swing arm 68, which in turn causes rotation of the interconnection 64 and upward swinging of arm 69 and locking element 60. There by, substantially simultaneous locking of the two extensions 54 and 55 is obtained.

When the ladder is again removed from the ground, the extensions will shift downwardly to cause the locking element 60 and '61 to return to their normal position shown in Fig. 6 and unlock the extensions.

The form of the invention shown in Figs. 8 to 12 employs the invention disclosed in the other figures in a slightly modified form. This form of the invention is shown applied to an article such as a table which must be supported at a multiplicity of points. The form shown discloses a table 80 employing 4 legs or supports 81, 8'2, 83 and 84, but the same invention could as well be applied to an article having a different number of legs. Extensions 85-88 are respectively mounted on the legs 81-84 for vertical sliding movement and are guided thereon by suitable means such as spaced guide rings 89-92 which are affixed to the corresponding table legs.-

Locking mechanisms 93-96 are provided on each of the respective table legs 8184 for locking the corresponding extensions in a desired vertical position. The locking mechanisms are substantially idential and for simplicity only two such mechanisms are shown in detail in Figs. 9 and 10, those being mechanisms 93 and 95.

Description of these two locking mechanisms is suflicient for an understanding of all of the locking mechanisms.

These locking mechanims 93 and 95 shown in detail are similar to the corresponding mechanisms shown in Figs. 1 to 4 and are provided with frictional locking elements 97 and 98 which in this form are disposed between the guide rings 89 and 91 respectively and which surround the respective extensions 85 and 87 to be swingable upwardly into frictional locking relation therewith. Means are also provided for restricting the vertical movement of these locking elements 97 and 98 and in the form shown such means comprise stop elements or brackets 99 and 100 which are affixed to the respective table legs 81 and 83 and each of which encloses projections 101 and 102 of locking elements 97 and 98 therein. The projections 101 and 102 carry annular rubber discs or cylinders 103 and 104 thereon which engage the stop members 99 and 100 when locking rings 97 and 98 are shifted and swung upwardly. Abutments 105 and 106 are afiixed'to the table le'gs 81 and 83 respectively for engaging the opposite end of the corresponding locking elements 9 7 and 98 to restrict dovmward movement thereof and to. support these locking elements in horizontal unlocked position.

'Means are also provided in this form of the invention for swinging the locking elements "97 and 98 upwardly in response to upward movement of the extensions 85 and '87 relative to their corresponding table legs 81 and 83. In the form shown, such means include actuating elements or lugs 107 and 108which are respectively secured to the extensions 85 and '87 and are disposed between the lower guide rings '89 and 91 and the locking elements 97 and 98. Actuating elements 107 and 108 are disposed to engage the locking elements 97 and 98 in spaced relation with the stop members 99 and 100 so as to cause upward swinging of the locking elements as the lugs are forced upwardly and into engagement with the stop members 99 and 100.

Means are provided for interconnectingeach of the locking mechanisms 93-916 to cause simultaneous operation thereof. A rotary interconnection 109 extends between the legs 81 and 82 and is journalled in bearings 1 10 which are afiixed to the cross-piece 111 extending between and atfixed to legs 81 and 82. Another rotary interconnection 112 extends bewteen table legs 82 and 83 and is journalled for rotary oscillation in bearings 1113 and 114 which are respectively mounted on the legs 82 and '83 by means of hinged brackets 115, as'best seen in Fig. 9. An interconnection 112 is provided with a device 116 to be hereinafter more fully described to permit shortening and lengthening of the interconnection. Bearings 11?: and 114 are constructed to freely slide along interconnection '12 for purposes hereinafter described.

Another rotary interconnection 117 which comprises a rigid rod or shaft, extends between the table legs 83 and 84 and is journaled in bearings 118 which are affixed to the cross-piece 119 which extends between and is affixed to the legs 83'and 84.

Means are provided for connecting the rotary interconnections 109, 112 and 117 together so as to effectively provide a single rotary interconnection extending to each of the table legs 81-84. Interconnections 112 and 117 are connected in the manner shown in detail in Fig. 9, and interconnections 109 and 112 are connected in an identical manner and the description of the apparatus for connecting the interconnections 112 and 117 will sufiice for an understanding of the entire structure. As best seen in Fig. 9, the rotary interconnections 112 and 117 are each provided with swing arms 112a and 117a connected at their ends and extending transversely thereof into'proximity with each other, one arm 112a extending above the other arm 117a. The bearing 118 spaces rotary interconnection 117 downwardly from the crosspiece 119 sutficiently to permit limited swinging movement of arm 117a. Arms 112a and 117a are interconnected by means of a rigid loop 120 which surrounds the same to cause simultaneous swinging thereof, and to permit the arms 112a and 117a to slide slightly into and out of the loop 120 as they swing.

The rotary interconnections are connected to each of the frictional locking mechanisms 9 396 by means of up-right push rods 121124. The rods 121124 are connected at their lower ends to the frictional locking elements of the respective locking mechanisms 93-96 in the manner indicated in detail in Figs. 9 and 10. As shown in these figures rods 121 and 123 have loops 125 and 126 which surround the outstanding projections 127 and 128 of locking elements 97 and 98 respectively. The loops 125 and 126 are retained on the projections by means of the washers 129 and 130 and cotter pins 131 and 132. Push rods 122 and 123 are connected to the. swing arms of the, rotaryinterconnections in the manner. shown in Fig. 9 and previously described wherein the loop. 120 is connected to the rod )123. RodslZ'l and 124. are; connected to the rotary interconnections i109 and 117 in the manner indicated in Fig. 10 wherein a loop .133 surrounds theswing, arrn109a of rod 109, and is retainedthereon by. means ofa washer 134 and cotter P n 5.-

It willbe seen that each of the locking elements of thetlocking mechanisms 93 -96 are connected to eachof the other locking elements through their corresponding push rods 121"124,and the rotaryinterconnections109, 1'12 and 1 17 so that when onelocking elementis swung upwardly into frictional locking relationwith its cor-re spending extension, each of the other locking elements is also swung upwardly into frictional: locking relation Wtih their respective extensions.

In the form shown the table 80 is constructed to be readily. and easily collapsed by swinging each pair of legs181,and 82 and 83 and. 84 upwardly into proximity with the bottom surface of the table top. The crosswpieces 111 and119; are connected to the table top by means of hinges .136 .and 137. To facilitate the upward swinging of the locking mechanisms and the rotary interconnections the bearings113 and 1-1-4 are swingably mounted on brackets 115 in the manner indicated in Fig. 9.

'. Brackets ,115 are connected by means of a hinge 138 to therespective table legs 82 and 83. The rotary inter-* connection 112 is provided wtih a device 116 which com prises a'sleeve 139 surrounding the end.,port i ons.140 and 141- of. the two sections of rodwhich makeup the rotary interconnection -.112. As best. seen inFigs'. 11 and12, the end portions 140 and 141 are semicircular in cross section and have opposed abutting surfaces 140;: and 14012 which cause the two end portions 140 and 141 to rotate simultaneously. The end portions 140 are free to slide toward and away from each other so-as to effectively shorten and lengthen interconnection 112.

In operation of the form of the inventionshown in Figs. 8-12 the table legs will normally be -positioned as shown in Fig. 8 and the locking elements of the locking mechanisms 93-96 will; be in downwardly. swung unlocked position. If the table. is thereafter placed upon a surface which is irregularly contoured or sloped certain .of the extensions 85-88 will engage the groundsurface before other extensions.

emplary of the invention and it is understood that the invention could be changed'in form, style'and arrange} ment without departing from the essence ofthe invention,

It,will be seen that we haveuprovided a new and jnovel apparatus which; issimple in construction and positive in operation for adjusting the relative lengths ofsupport legs for anarticle so that with a minimum of'difliculty and inconvenience the article may be placed in a desired position on even an irregularly slopedor contoured surface by merely manually holding the article in its desired position and placing it uponthe surface.

Suitable means may be provided for holding the table legs 81-84 in their dependingpositions when-the table is in use. Such means may comprise braces 142 hingedly secured to the cross-pieces 111 and-119 and releasably secured to the bottom surface of the table top as by hooks It will, ofcourse, belunderstood; thatvarious changes may be made inthe form," detail, arrangement and proportion of -the parts without departing from thescopeof my invention :which consistsofthe matter described :herein and set forth in the appended claims.

What weclaim is: I I 1. In apparatus for supporting an article in a desired position on a surface which may be uneven, said apparatus comprising a pair of supports securable to such an article, apair of elongated extensions each individually slidable ona respective. support, a pair ofifrictional locking elements each'engaging a respective extension and being swingableinto frictionalnlocking relation therewith, means connecting said *lockingelements with the supports and including a shaft extending between saidsupports and being mounted-thereon for rotary oscillation and having the ends thereof; connected with said locking elements to swing. the same simultaneously, whereby swinging of one of said: locking elements into locking relation on-its respective. extension. causes the other element to lock its corresponding extension. 2. Apparatus for supportingan article. in a desired position on an uneven surface; said'apparatus comprising a pair of legs securable to such an article, a pair of depending extensions mounted on said legs for. vertical sliding, a pair of frictional-locking elements eachrengaging'a respective extension and-being swingable up.- wardl-y into frictional locking. relaticn therewith, means connecting the locking elements with the: legsand-with each other and including a pair of stop members each mounted ona respective leg adjacentth'ecorresponding extension and disposed above the-lockingselement for engaging and fulcruming the same into lockingrel'ation with the extension, and saidmeansalso. including an elongate shaft extending between the. legs and being mounted thereon for rotary oscillation; the ends of-th'e shaft being respectively connected with the'locking'ele ments for producing simultaneous swinging thereof,

' element upwardly toward lockingposition upon upward movement of the extension, whereby said actuating means and shaft will cause simultaneous swinging of said locking elements into locking relation with their corresponding extensions.

= 4. In apparatus for supporting an article in a desired position on a surface which may be uneven, a plurality of supports securable to such an article, a corresponding number of depending extensions each mounted on a respective support for vertical sliding to engage such a surface, a corresponding number of frictional locking elements each engaging a respective extension and being swingable into frictional locking engagement therewith, means fulcrumingthe locking elements with respect to the corresponding supports, an interconnection extending between adjacent pairs of said supports and being mounted thereon for rotary oscillation about an axis extending from one support to the other support, said locking elements being connected with said interconnecting element for oscillating the same when swung, whereby when one of said locking elements is swung into locking position, all of said extensions will be locked substantially simultaneously by their corresponding locking elements.

'5. In apparatus for supporting an article in a desired position on a surface which may be uneven, said apparatus comprising at least three supports securable to such an article, at least three depending extensions each mounted on a respective support for vertical sliding and for engaging such a surface, at least three frictional locking elements each engaging a respective extension and being swingable upwardly into frictional locking relation therewith, means connecting the locking elements with the supports and with each other and including shaft means extending between adjacent pairs of said supports and being mounted thereon for rotary oscillation about axes extending transversely of the supports, means connecting said shaft means to the locking elements to produce simultaneous swinging ofall the locking elements, whereby all of said extensions may be locked substantially simultaneously with simultaneous swinging of said interconnected locking elements and thereby support such an article in a desired position on such a surface.-

,6."In apparatusvfo'r supporting an article in a desired position on a surface which may be uneven, a pluraltiy of supports securable to such an article, a corresponding number of elongated and substantially parallel extensions each slidably mounted on a respective support for engaging such a surface, a corresponding number of frictional locking elements each engaging a respective extension and being swingable into frictional locking relation therewith, a plurality of stop elements each mounted on a respective support adjacent the corresponding extensionand above the corresponding locking element for engagement therewith, an elongate and substantially rigid interconnection extending between adjacent pairs of said supports and being mounted thereon for rotary oscillation about longitudinalaxes, means connecting said locking elements to said interconnection to cause rotary oscillation of the interconnection when said lockingelements are swung, and a plurality of actuating elements eachconnected with a respective extension and mounted to-swing the correspondinglocking element into frictional locking relation with the corresponding extension after all of said extensions have. engaged such a surface, whereby when said extensions are caused to engage such a surface, one of said actuating elements will engage and swing its corresponding locking element, the motion of which is transmitted to other locking elements to simultaneously lock all of said extensions. 7. .In apparatus for supporting an article on a surfac that may be uneven, the combination of a pair of supports, a pair of depending extensions each mounted on aJrespective corresponding support for vertical sliding,

a pair of locking elements each. having opposed frictional gripping portions "disposed in proximity with opposite sides of a corresponding extension to be swung into locking frictional engagement therewith, stop means connected to said supports for limiting upward movement of one of said gripping portions of each of said locking elements, a rotary interconnection extending between said supports and mounted thereon for rotary oscillation, means connecting said rotary interconnection with said locking elements to cause simultaneous swinging thereof, and means connected with at least one of said extensions for urging the corresponding locking element in an upward direction when both extensions have engaged the ground to swing said locking element into frictional locking relation with the corresponding exten-; sion, whereby the swinging motion will be transmitted through said arms and said interconnection for swinging the other locking element into frictional locking position.

8. The structure recited in claim 3 andincluding stop members each mounted on a respective support adjacent the corresponding extension and above the locking element for engaging the locking element when swung upwardly, and said actuating element engaging the corresponding locking element in spaced relation transversely of said extension from said stop member, whereby said stop members will fulcrum said locking elements when the same are swung upwardly by said actuating elements.

9. In apparatus for supporting an article in a desired position on a surface, said apparatus comprising a pair of supports securable to such an article, a pair of elongated extensions each slidably mounted on a respective support, a substantially rigid interconnection extending between said supports and being mounted thereon for rotary oscillation, a pair of frictional locking elements each engaging a respective extension and being swingable into frictional locking relation therewith, said locking elements being connected with said interconnection for simultaneous swinging, and an actuating lug mounted on one of said extensions and positioned to engage and swing the corresponding locking element into locking relation with the corresponding extension when both extensions have engaged the ground, whereby the positive movement of one of said locking elements caused by said lug will be transmitted to the other of said locking elements for substantially simultaneously locking both ex-- tensions. 1 5

10. In apparatus for supporting an article in a desired position, even on an irregular and uneven surface, saidapparatus comprising a pair of supports securable to such an article, a pair of depending extensions each mounted on a respective support for vertical sliding, a substan-' tially rigid interconnection extending between said sup-- ports and being mounted thereon for rotary oscillation, a pair of frictional locking elements each engaging a respective extension and being swingable upwardly into frictional locking relation therewith, said locking elements being connected with said interconnection for simultaneous swinging, and an actuating element mounted for vertical adjustment on one of said extensions and positioned to engage the correspondinglocking-element and swing the same upwardly into locking position when both extensions have engaged such a surface, whereby said element may be vertically adjusted to adapt the apparatus for use on surfaces of vastly different contours and slopes and also to adapt the apparatus for locking the supports and the article in different vertical positions.

11. In apparatus for supporting an article in a desired position on a surface which may be uneven, said apparatus comprisin a pair of supports securable to such an article, a pair of depending extensions each mounted on a respective support for vertical sliding, and a substantially rigid interconnection extending between said supports and being mounted thereon for rotary oscillation, a pair 'of frictiona1 locking elements each engaging a respective extension and being swingable upwardly into frictionallocltingre;

13 lation therewith, said locking elements being connected with said interconnection for simultaneous swinging, a pair of friction shoes each mounted for swinging a respective locking element upwardly and each frictionally engaging the corresponding extension to be urged upwardly thereby when the same is moved upwardly with respect to the corresponding support, the friction between said friction elements and said extensions being sufficient to move the friction shoes and interconnected locking elements upwardly when both extensions slide upwardly with respect to said supports, whereby when both of said extensions engage such a surface said extensions will be substantially simultaneously locked to support the article in the desired position.

12. In apparatus for supporting an article in a desired position on a surface which may be uneven, said apparatus comprising a pair of supports securable to such an article, a pair of upright extensions each mounted on a respective support for vertical sliding, a substantially rigid interconnection extending between said supports and being mounted thereon for rotary oscillation, a pair of frictional locking elements each engaging a respective extension and being swingable into frictional locking relation therewith, said locking elements being connected with said interconnection for simultaneous swinging, a pair of friction shoes each frictionally engaging a respective extension and each connected with the corresponding locking element for urging the same upwardly when said extension is moved upwardly with respect to the corresponding support, and a pair of resiliently yieldable members each engaging and urging a respective friction shoe toward the corresponding extension to control the friction between the shoe and the corresponding extension, the

friction between one shoe and the corresponding exten-.

sion being insufficient to swing the interconnected lock- 14 ing elements upwardly into locking position when only the last mentioned extension is shifted upwardly, and the combined friction between said shoes and said extensions being sufiicient to swing the interconnected locking elements upwardly to locking position when both extensions are shifted upwardly with respect to said supports.

13. In apparatus for supporting an article in a desired position on a surface which may be uneven, said apparatus comprising a pair of supports securable to such an article, a pair of elongated extensions each slidably mounted on a respective support, said extensions having outer end portions for engaging such a surface, a pair of resiliently yieldable elements each bearing against a respective extension and the corresponding support and urging the extension outwardly toward such a surface, a substantially rigid interconnection extending between said supports and being mounted thereon for rotary oscillation, a. pair of frictional locking elements each engaging a respective extension and being swingable to frictional locking relation therewith, said locking elements being connected with said interconnections for simultaneous swinging,

whereby said extensions will be urged outwardly from said supports when said locking elements are swung out of locking relation with their corresponding extensions.

References Cited in the file of this patent UNITED STATES PATENTS 1,792,714 Shields Feb. 17, 1931' 2,176,551 Solem Oct. 17, 1939 2,281,769 Hochriem May 5, 1942 2,289,499 Husted July 14, 1942 2,413,342 Symons Dec. 31, 1946 2,448,630 Schutz Sept. 7, 1948 2,555,036 Husted May 29, 1951 

